Host Microbe Interactomics, Department of Animal Science, Wageningen University & Research, Wageningen, Netherlands.
Top Institute Food and Nutrition, Wageningen, Netherlands.
Front Immunol. 2018 Oct 12;9:1972. doi: 10.3389/fimmu.2018.01972. eCollection 2018.
There is much interest in the immunomodulatory properties of dietary fibers but their activity may be influenced by contamination with microbial-associated molecular patterns (MAMPs) such as lipopolysaccharide (LPS) and lipoteichoic acids, which are difficult to remove completely from biological samples. Bone marrow-derived dendritic cells (BMDCs) from TLR2x4 double-KO mice were shown to be a reliable approach to analyse the immunomodulatory properties of a diverse range of dietary fibers, by avoiding immune cell activation due to contaminating MAMPs. Several of the 44 tested dietary fiber preparations induced cytokine responses in BMDCs from TLR2x4 double-KO mice. The particulate fractions of linear arabinan (LA) and branched arabinan (BA) from sugar beet pectin were shown to be strongly immune stimulatory with LA being more immune stimulatory than BA. Enzymatic debranching of BA increased its immune stimulatory activity, possibly due to increased particle formation by the alignment of debranched linear arabinan. Mechanistic studies showed that the immunostimulatory activity of LA and BA was independent of the Dectin-1 recognition but Syk kinase-dependent.
人们对膳食纤维的免疫调节特性非常感兴趣，但它们的活性可能会受到微生物相关分子模式（MAMPs）的污染的影响，例如脂多糖（LPS）和脂磷壁酸，这些物质很难从生物样本中完全去除。TLR2x4 双敲除小鼠的骨髓来源树突状细胞（BMDCs）是一种可靠的方法，可以通过避免因污染的 MAMPs 而导致免疫细胞激活，来分析各种膳食纤维的免疫调节特性。在 TLR2x4 双敲除小鼠的 BMDCs 中，有 44 种测试的膳食纤维制剂中的几种诱导细胞因子反应。从糖甜菜果胶中提取的线性阿拉伯聚糖（LA）和支链阿拉伯聚糖（BA）的颗粒部分被证明具有很强的免疫刺激性，其中 LA 的免疫刺激性强于 BA。BA 的酶解分支增加了其免疫刺激性活性，这可能是由于去分支的线性阿拉伯聚糖的排列增加了颗粒的形成。机制研究表明，LA 和 BA 的免疫刺激活性不依赖于 Dectin-1 的识别，而是依赖于 Syk 激酶。
